Abstract
Purpose: :
The majority of patients with Stargardt disease (STGD) develop an eccentric preferred retinal location (PRL). To investigate the possible physiopathological mechanisms underlying the development of eccentric PRLs in STGD patients a morphological and functional study of the retinal areas associated with the PRLs was performed.
Methods: :
Fifty-three STGD patients (32 from the Eye Clinic in Florence and 21 from Columbia University in New York) with at least one ABCA4 mutation aged 37.68 +/- 18.01 (range 15-68 yrs.) with visual acuities >=20/200 were recruited. The following tests were performed: fundus-controlled perimetry with the Nidek MP-1 (10-2 program, 4-2 procedure with 2° fixation cross), fundus autofluorescence imaging (Heidelberg Retinal Angiograph 2), spectral domain optical coherence tomography (SD-OCT Cirrus and Topcon 1000, macular cube 512 x 128 scan pattern and raster lines). The location, stability of the PRLs and the associated visual sensitivities were determined and compared to the underlying retinal structure.
Results: :
For 92 eyes of 53 patients the PRL was foveal in only 13 eyes and eccentric in 79 (superior to the fovea in 68 eyes, nasal in 7, temporal in 4 and inferior in none). Fixation was stable in 23 eyes (9 with foveal fixation), relatively unstable in 53 and unstable in 16. For the 79 eyes with eccentric PRLs, the PRL was 1.5° to 14° from the fovea (mean value 5.57°); for 32 eyes it was at the edge of the macular atrophy and for 45 eyes it was located 1.5° to 11.5° (mean value 4.95°) from the border of the atrophic area. The eccentric PRL was associated with significantly increased visual sensitivity compared to the foveal area (mean value 10.24 +/- 4.89dB) and with an intact inner/outer segment (IS/OS) junction on SD-OCT. The area between the atrophic lesion and eccentric PRL was associated with markedly decreased sensitivity on the MP-1 (mean value 6.98 +/- 4.43dB) and with loss of the IS/OS junction. The area of morphological and functional retinal abnormalities was more extensive than the atrophic lesion identified by fundus autofluorescence imaging.
Conclusions: :
In a group of STGD patients a multimodal analysis of retinal areas associated with the PRLs demonstrates that PRLs are associated with increased visual sensitivity and preserved IS/OS junction; this analysis improves our understanding of the physiopathological mechanisms determining the location of eccentric PRLs.
Keywords: retinal degenerations: hereditary • imaging/image analysis: clinical